A conventional vehicle door control system controls locked and unlocked states of every door of a vehicle in accordance with a result of collating identification (ID) codes through duplex communications between a hand-held electronic key serving as a hand-held device and a vehicle-side electronic unit. In this vehicle door control system, a predetermined communication area surrounding the vehicle is set and, in this communication area, a transmitter employed in the vehicle-side unit transmits a request signal typically at predetermined intervals. Thus, the conventional vehicle door control system monitors movements of the holder of the hand-held device as movements approaching the vehicle, getting on the vehicle and getting off from the vehicle.
When the holder of the hand-held device approaches the vehicle in order to get on the vehicle, for example, the holder of the hand-held device enters the predetermined communication area. At that time, the hand-held device transmits a response signal including an ID code to the vehicle-side unit in response to the request signal. The vehicle-side unit determines whether or not the ID code satisfies a predetermined relational condition typically by examining whether or not the ID code matches an ID code registered in advance in the vehicle-side unit. When the ID code satisfies the relational condition, a control signal is supplied to a door locking control device employed in the vehicle-side unit to put every door in an unlock standby state. With every door put in the unlock standby state and a hand of the holder of the hand-held device touching a door handle of any specific door, a touch sensor employed in the door locking control device detects the touch and the door locking control device unlocks the specific door to allow the holder of the hand-held device to enter the vehicle compartment.
In addition, when the holder of the hand-held device gets off from the vehicle through a door of the vehicle after turning off an engine, a communication area of the hand-held device moves from the compartment of the vehicle to the outside thereof. At that time, when a door locking switch provided at a location in close proximity to the door handle of the door is operated, the door is locked.
In accordance with the above conventional vehicle door control system, the holder of the hand-held device is capable of locking and unlocking every door of the vehicle without manually operating a hand-held device and, thus, enjoying enhanced user friendliness of the vehicle door control system.
When the holder of a hand-held device gets off from the vehicle and wants to lock every door of the vehicle, for example, the holder of a hand-held device operates an opening/closing switch included in the hand-held device as an opening/closing switch of the vehicle doors to drive the automatic opening/closing apparatus to close the vehicle doors, which were opened when the holder of the hand-held device got off from the vehicle. After that, the holder of the hand-held device operates a lock switch provided on a door of the vehicle in order to lock all the doors of the vehicle. In this way, the vehicle door control system and the automatic opening/closing apparatus operate independently of each other in spite of the fact that the controlled doors of the vehicle are doors common to the vehicle door control system and the automatic opening/closing apparatus.
To solve the above drawback, a vehicle door control system is proposed, which carries out a sequence of consecutive operations to drive the automatic opening/closing apparatus to close the doors employed in the vehicle and then lock the doors when triggered by an operation carried out by the user on the doors. That is, when an operation carried out by the user on the doors is detected with the doors opened, ID codes are collated with each other. When the result of the collation is an OK, an operation to close the doors and an operation to lock the doors are carried out in succession. Thus, the user need not carry out operations to close the doors employed in the vehicle and lock the vehicle doors at two stages. To be more specific, the user need not carry out an operation to automatically close the doors employed in the vehicle at a first stage and, then, carry out an operation to lock the vehicle doors at a second stage. As a result, the user can enjoy more user friendliness.
In addition, it is preferable to carry out a process in order to make sure that the hand-held device is not left behind in the compartment of the vehicle with all the vehicle doors put in a locked state in order to avoid the risk of leaving the hand-held device in the compartment due to the fact the user has forgotten to take along the hand-held device with the user when the user gets off from the vehicle. In order to carry out such a process, an internal transmitter provided in the compartment of the vehicle as a transmitter having a communication area covering only the compartment of the vehicle is driven to transmit a request signal. When a response signal is received from the hand-held device as a signal transmitted by the hand-held device in response to the request signal transmitted by the compartment internal transmitter, the vehicle door control system determines that the hand-held device has been left behind in the compartment of the vehicle. When a response signal is not received from the hand-held device, on the other hand, the vehicle door control system determines that the hand-held device has not been left behind in the compartment of the vehicle.
When the compartment internal transmitter transmits a request signal when the user operates a door employed in the vehicle with doors of the vehicle each put in an open state, however, it is likely that the communication area of the transmitted request signal is extended from the compartment internal area to also cover an area outside the compartment due to the fact that any of vehicle doors are in the open state. In this case, a response signal may be received from the hand-held device as a signal transmitted by the hand-held device in response to the request signal transmitted by the compartment internal transmitter in spite of the fact that the hand-held device is located outside the compartment of the vehicle. Since the vehicle door control system determines that the hand-held device has been left behind in the compartment of the vehicle in this case, however, the sequence of consecutive operations to drive the automatic opening/closing apparatus to close the doors employed in the vehicle and then lock the doors cannot be carried out.